Fwd: Re: [meteorite-list] Brahin stability

From: Steve Schoner <steve_schoner_at_meteoritecentral.com>
Date: Thu Apr 22 10:30:29 2004
Message-ID: <20030930152920.37282.qmail_at_web12702.mail.yahoo.com>

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Received: from [66.53.75.135] by web12702.mail.yahoo.com via HTTP; Tue, 30 Sep 2003 08:26:29 PDT
Date: Tue, 30 Sep 2003 08:26:29 -0700 (PDT)
From: Steve Schoner <steve_schoner_at_yahoo.com>
Subject: Re: [meteorite-list] Brahin stability
To: Martin Altmann <Altmann_at_Meteorite-Martin.de>
In-Reply-To: <008b01c3874a$195a8c00$aad1e4d9_at_9y6y40j>
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There are several ways of dealing with the NiFe2-FeCl3
(Lawrencite) problem.

1) Coatings and sealers:
Polish and etch the specimen, then completely dry it
in an oven then hot dip into a sealant and allow it to
cool. Remove, allow it to dry, then coat it several
times more to make sure that the coating is strong and
thick enough to prevent moisture from passing. This
will work, but only as much as the sealant allows.
Nickel and iron chlorides are extremely hydroscopic,
they suck water from the air, no matter how little
humidity there is. And once water is present, then
the chlorine is "unhooked" to attach to free Fe and Ni
atoms to start a catalytic reaaction with the water
and surronding air to reduce the meteorite to oxides.
So, unless the chlorine can be dealt with, and
removed, the proceess will continue.

2) Neutralization:
Rid the specimenen of chlorine. The use of chemical
bases, such as sodium hydroxide, and or sodium
bi-carbonate are very effective in neutralizing the
chlorides. Depending on the specimen the samples must
be soaked in solutions containing these for weeks if
not months. When the process is over, allow for air
drying. Leave the surface as it is with rust spots
and all. If the specimen is stable, then re-polish
the surface. Allow it to sit with out coating for
several weeks, and if nothing happens, and no rust
appears. On a nice dry day, coat the specimen with a
protective coating. (But I like to leave most of my
specimens without such coatings. If they are stable
without, it is best to leave them that way.

For very bad rusters, using a light current in the
millivolt range where the meteorite is the anode and
the containment vessel is the cathode and the
electrolyte a solution of NaOH might help in the
process. (Before my recent illness I was going to
attempt this on some pieces, and had the procees layed
out in my computer. I can't find it now. So, I must
start over again.) This is a technique that is used
by relic hunters that find iron objects on the ocean
bottom. It works very well and the chlorides of iron
have been completely removed using this technique.

3) Vapor emitters:
I have no experience with these. But they might work
on some meteorites, but not all, especially those that
have high concentrations of iron and nickel chlorides.
 When moisture is present, then these chlorides will
extract moisture from the air, producing droplets of
chloride rich water on the specimen, which I think
with or without the new vapor emmiters will contine
the process of rusting.

There is really only two ways to deal with meteorite
rusting from chlorides.

Completely seal the specimen from air with lots of
dessicant. Just putting them in a box that is
accessible to air is not enough. You need an airtight
box. Or Neutralize the chlorides by chemical means.

I see no other ways.

Steve Schoner
http://www.geocities.com/american_meteorite_survey







--- Martin Altmann <Altmann_at_Meteorite-Martin.de>
wrote:
> Hi again,
>
> does anyone has experiences with the Brahins from
> Koutyrev/finmet?
> He praises them to be totally stable for years (you
> can put in salt
> water..), due to a new method.
> I wonder, how he could know that his method helps,
> as he uses it obviously
> not longer than a year or so (as far as I observed
> his auctions).
>
> From one of Serge's pieces I grinded off (dry) the
> glue, for testing, what
> will happen. It started immediately to develope rust
> traces and after 2
> months, it was so swollen (lawrencite?) that I hid
> away for not getting hurt
> in a potential explosion.
>
> Martin
>
> ----- Original Message -----
> From: "Zelimir Gabelica" <Z.Gabelica_at_uha.fr>
> To: <meteorite-list_at_meteoritecentral.com>
> Sent: Tuesday, September 30, 2003 12:21 PM
> Subject: [meteorite-list] Brahin stability
>
>
> Hello Martin, Matteo, John, Tim, all,
>
> I also got a Brahin slice from Afanasjev 3 years
> ago, mint and not
> lacquered. It started getting rust spots after a
> couple of weeks and was
> almost completely destroyed after 6 months.
> I realize that Serge now found a way to protect
> Brahins but I did not dare
> to take another such lacquered one from him last
> June in Ensisheim.
> The only Brahin I acquired since this disappointing
> experience is a slice
> embedded forever in epoxy. This is an exception as I
> never do that for
> meteorites but after 3 unfruitful attempts to get a
> stable Barahin (from 3
> various sources), I opted for the epoxy solution.
> The message is probably that every meteorite
> candidate to rusting could
> (should) first be treated in some way (like, e.g.
> the NaOH-propanol method
> decribed by Steve Schoner) and then protected (e.g.
> Afanasjev's "kind of
> glue").
> Still much work and many "trials & errors" in
> perspective, as every case
> seems to be diferent...
>
> Cheers,
>
> Zelimir
>
>
> At 10:32 30/09/03 +0200, you wrote:
> >Hi Matteo,
> >
> >I had several slices of Brahin from Afanasjev,
> which were lacquered with a
> >kind of glue. Kept in an airtight box with dry
> agent they were totally
> >stable for 2 years, another slice I had more than 6
> years without any
> >problems and as far as I know, they are still all
> o.k.
> >
> >Cheers!
> >(Imilac is the best!)
> >
> >----- Original Message -----
> >From: "M come Meteorite Meteorites"
> <mcomemeteorite2000_at_yahoo.it>
> >To: <meteorite-list_at_meteoritecentral.com>
> >Sent: Tuesday, September 30, 2003 7:27 AM
> >Subject: Re: [meteorite-list] Pallasite available?
> >
> >
> >> Here all Brahin pieces is go destroyed in 1 month
> or
> >> few months, the unique piece stable is a slice
> buy 7
> >> years ago from Casper. For no speack of Brenham,
> >> Quijnque, Albin, Admire. No problems with Esquel
> and
> >> Imilac. Sincerely if I should spend some money I
> would
> >> spend them on a slice of Imilac or Esquel how I
> did,
> >> my slice of Imilac from 94 gr. is perfect after 5
> >> months, a slice of brahin after this time is go
> >> destroy in 4 pieces.
> >> Regards
> >>
> >> Matteo
> >>
> >> --- John Gwilliam <jkg_at_theriver.com> wrote:
> >> > I agree with Tim (and several other list
> members) on
> >> > this one. There are
> >> > some Brahin specimens available that are very
> >> > stable.
> >> >
> >> > Best,
> >> > John Gwilliam
> >> >
> >> > At 05:48 PM 9/29/03 -0500, Tim Heitz wrote:
> >> > >Matteo,
> >> > >
> >> > >NO ITS NOT all rusty !!!! Not all
> >> > >
> >> > >Regards,
> >> > >Tim Heitz
> >> > >
> >> > >
> >> > >----- Original Message -----
> >> > >From: "M come Meteorite Meteorites"
> >> > <mcomemeteorite2000_at_yahoo.it>
> >> > >To: <bernd.pauli_at_paulinet.de>;
> >> > <meteorite-list_at_meteoritecentral.com>
> >> > >Sent: Sunday, September 28, 2003 11:23 PM
> >> > >Subject: Re: [meteorite-list] Pallasite
> available?
> >> > >
> >> > >
> >> > > > Yes, but brahin is a rusty bastard
> pallasite.
> >> > > > Regards
> >> > > >
> >> > > > Matteo
> >> > > >
> >> > > > --- bernd.pauli_at_paulinet.de wrote:
> >> > > > > > Hello, Would any one happen to have a
> small
> >> > slice
> >> > > > > of a Pallasite
> >> > > > > > for sale or maybe trade? I do not have
> one
> >> > in my
> >> > > > > collection and
> >> > > > > > figure it is time. I am looking for a
> small
> >> > slice
> >> > > > > that has plenty of
> >> > > > > > both materials for my viewing pleasure.
> : )
> >> > > > >
> >> > > > > What about these:
> >> > > > >
> >> > > > >
> >> > > >
> >> >
> >>
>
>>http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&category=3239&item=219364678
> 0
> >> > > > >
> >> > > > >
> >> > > >
> >> >
> >>
>
>>http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&category=3239&item=219348466
> 9
> >> > > > >
> >> > > > >
> >> > > >
> >> >
> >>
>
>>http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&category=3239&item=219348472
> 9
> >> > > > >
> >> > > > > The "2193646780" Brahin would be my
> favorite
> >> > though
> >> > > > > the "2193484729"
> >> > > > > Brahin is very nice too. The former looks
> more
> >> > > > > stable visually.
> >> > > > >
> >> > > > > Several months ago I got a nice little
> >> > QUIJINGUE
> >> > > > > (3.5 grams) from AL Mitterling via
> >> > > > > Ebay and it is still very stable. Keep
> your
> >> > hands
> >> > > > > off ADMIRE - it is a rust bucket lest
> >> > > > > you take care of it regularly. Esquel and
> >> > Imilac
> >> > > > > slices are quite stable, my Brenham
> >> > > > > has been stable for more than 15 years
> now -
> >> > others
> >> > > > > have had less luck because with
> >> > > > > Brenham it depends on whether it is an
>
=== message truncated ===


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